JP3750405B2 - Blast furnace operation method during blast furnace inner wall repair - Google Patents
Blast furnace operation method during blast furnace inner wall repair Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、高炉内壁を耐火物で吹付け補修した際の、耐火物の高炉内への落下物（以下、「リバウンドロス」という）に起因する通気性や通液性、荷下がりの悪化を抑制して円滑な操業を行うことができる高炉炉内壁補修時における高炉操業方法に関するものである。
【０００２】
【従来の技術】
近年、高炉の炉命延長により炉内壁の損傷が激しくなっている。そこで、特公昭６０−２４１６１号等に炉内壁損傷部への不定形耐火物の吹付け方法が開示されているが、炉内壁に吹付けた耐火物の５〜５０％は炉壁損傷部に付着せずに炉内装入物上に落下し、炉内原料表面で固着して操業再開後の高炉内の通気性や通液性を阻害するという問題があった。
【０００３】
そこで、本出願人は、特開平１０−４６２１７号で、炉内原料表面で固着したリバウンドロスを破砕し、高炉内の通気性等を改善する方法を開示した。
【０００４】
【発明が解決しようとする課題】
しかしながら、リバウンドロスの含有成分は耐火物の成分そのものであり、一般的には高融点であるため、例え破砕されても高炉内で溶融され難い。また、その溶融物も流動性が悪いために、高炉内の通気性や通液性を悪化させ、時には降下停滞や急速降下などの装入原料の降下異常を引き起こす場合がある。従って、リバウンドロスをそのままの成分で高炉内に堆積させることは、円滑な高炉操業を行うためには好ましくない。
【０００５】
本発明は、上記した問題点に鑑みてなされたものであり、リバウンドロスの成分を、高炉に装入するフラックス原料の成分で、通常操業時とほぼ同じスラグ成分となるように調整することで、スラグ性状を改善し、高炉内の通気性や通液性を良好にし、円滑な操業を行うことができる高炉炉内壁補修時における高炉操業方法を提供することを目的としている。
【０００６】
【課題を解決するための手段】
上記した目的を達成するために、本発明の高炉炉内壁補修時における高炉操業方法は、リバウンドロス量と、高炉内への落下時のスラグ成分を予測し、この落下したリバウンドロスが高炉内で溶融する時に、通常のスラグ成分とほぼ同じ成分となるように、耐火物吹付けを実施する直前及び直後、または、直前或いは直後に、フラックス原料を単独、或いは、コークス又は鉱石と共に高炉内に装入するのである。そして、このようにすることで、高炉内スラグ性状が改善され、高炉内の通気性や通液性が良好になる。
【０００７】
【発明の実施の形態】
リバウンドロスの量は、本発明者らの実績では、通常、吹付け量の１０〜３０％程度である。
また、リバウンドロスの成分は、耐火物の成分そのものであり、一般的に高炉の炉内壁補修に使用される吹付け材中には、高融点化合物である酸化アルミニウム（Ａｌ2 Ｏ3 ：融点２０５０℃）が２０〜７０％程度含まれていて、融点が１６００℃以上となっている。従って、リバウンドロスは高炉内での溶融が困難である。
【０００８】
一方、通常の高炉スラグ中のＡｌ2 Ｏ3 含有量は１０〜１６％程度であり、それ以外の成分、例えばＣａＯ，ＳｉＯ2 等と混合されて融点１４００℃以下のスラグとなっているので、高炉内での溶融は容易である。また、高炉スラグ中のＡｌ2 Ｏ3 含有率が高いと、高炉スラグの流動性が悪化し、溶銑との分離不良や出銑不良等の原因となる。
【０００９】
従って、リバウンドロスを含むスラグの成分を、通常時と同じ成分、特にＡｌ2 Ｏ3 の含有率を１６％以下にするには、ＣａＯやＳｉＯ2 を多く含む石灰石、珪石、蛇紋岩等のフラックス原料、或いは、高炉スラグを、単独或いは混合して、耐火物を吹付ける直前及び直後、または、直前或いは直後に高炉内に装入してスラグ成分を調整する必要がある。なお、装入原料はフラックス原料、高炉スラグだけに限らず、コークスや鉱石と混合させても良い。
【００１０】
本発明の高炉炉内壁補修時における高炉操業方法は、上記した考え方に基づいて成されたものであり、高炉の休風時に高炉炉内壁を耐火物で吹付け補修するに際し、リバウンドロス量と、高炉内への落下時のスラグ成分を予測し、この落下したリバウンドロスが高炉内で溶融する時に、通常のスラグ成分とほぼ同じ成分となるように、吹付けを実施する直前及び直後、または、直前或いは直後に、フラックス原料を単独或いはコークス又は鉱石と共に高炉内に装入するものである。
【００１１】
本発明の高炉炉内壁補修時における高炉操業方法において、リバウンドロスの予測量は、過去の実績値、実験値、或いは、耐火物製造者の推測値等を参考にして予測する。
【００１２】
本発明の高炉炉内壁補修時における高炉操業方法は、リバウンドロスが高炉内で溶融する時に、通常の高炉スラグの成分と同程度となるように、吹付けを実施する直前及び直後、または、直前或いは直後に、フラックス原料を単独或いはコークス又は鉱石と共に高炉内に装入するので、高炉内スラグ性状が改善され、高炉内の通気性や通液性が良好になる。
【００１３】
【実施例】
以下、本発明の高炉炉内壁補修時における高炉操業方法を、実施例に基づいて説明する。
（実施例１）
内容積２７００ｍ3 、炉口径８．４ｍの高炉において、炉壁損傷部以下に装入物レベルを減尺した後休風し、炉壁損傷部に不定形耐火物の乾式吹付け補修を計画した。この際、本発明の方法を採用して、吹付け量３０トンに対してリバウンドロスを１５％（４．５トン）と想定し、第１回目のスラグ成分を下記表１に示す通常操業時のスラグ成分とほぼ同じにするため、フラックス原料のうち、蛇紋岩と石灰石を吹付け実施直前に高炉内に装入した。この装入した蛇紋岩、石灰石の成分を下記表２に、また、装入量を表３に、この蛇紋岩と石灰石を装入した後の予測スラグ成分を下記表４に示す。なお、蛇紋岩と石灰石の装入量の決定方法としては、先ずＡｌ2 Ｏ3 が通常スラグの含有量となるように、石灰石と蛇紋岩の総量を決定し、次に、ＣａＯ／ＳｉＯ2 が通常スラグの時の値となるように石灰石と蛇紋岩の割合を決定する。
【００１４】
【表１】
【表２】
【表３】
【表４】
作業終了後、操業を再開したところ、炉内通気性が悪化して送風圧力が上昇したり、原燃料の降下異常（降下停滞や急速降下）等の減少は見られず、第１回目に排出したスラグ成分は、通常操業時のスラグ成分とほぼ同じで、操業諸元も通常操業に順調に復帰した。第１回目に排出したスラグ成分を表５に示す。
【００１９】
【表５】
（実施例２）
内容積２７００ｍ3 、炉口径８．４ｍの高炉において、炉壁損傷部以下に装入物レベルを減尺した後休風し、炉壁損傷部に不定形耐火物の乾式吹付け補修を計画した。この際、本発明の方法を採用して、吹付け量３０トンに対してリバウンドロスを１５％（４．５トン）と想定し、第１回目のスラグ成分を上記表１に示す通常操業時のスラグ成分とほぼ同じにするため、フラックス原料のうち、上記表２に示す成分の蛇紋岩と石灰石を、また、休風時間が長時間となるため炉体からの抜熱等の熱低下分の保証としてコークスを、吹付け実施直前に高炉内に装入した。この装入した蛇紋岩、石灰石の装入量を表６に、これら、コークス、蛇紋岩、石灰石を装入した後の予測スラグ成分を表７に示す。
【００２１】
【表６】
【表７】
休風後、炉壁損傷部を観察したところ、予想以上に損傷が激しく、吹付け量を４０トン（想定リバウンドロス量は６．０トン）にすることにした。従って、前記表６に示した量の蛇紋岩、石灰石を装入しただけでは、表７に示したような予想スラグ成分とはならず、下記表８に示すようなスラグ成分となるように予想される。この予想では、スラグ中のＡｌ2 Ｏ3 は１６．６％となって通常操業時よりも大幅に高くなり、炉内通気性が悪化して送風圧力の上昇や、原燃料の降下異常が予想されるため、吹付け直後にも蛇紋岩と石灰石を装入した。吹付け直後の装入量を表９に、この蛇紋岩と石灰石を装入した後の予想スラグ成分を表１０に示す。
【００２４】
【表８】
【表９】
【表１０】
作業終了後、操業を再開したところ、炉内通気性が悪化して送風圧力が上昇したり、原燃料の降下異常等の減少は見られず、第１回目に排出したスラグ成分は、通常操業時のスラグ成分とほぼ同じで、操業諸元も通常操業に順調に復帰した。第１回目に排出したスラグ成分を表１１に示す。
【００２８】
【表１１】
（従来例）
内容積２７００ｍ3 、炉口径８．４ｍの高炉において、炉壁損傷部以下に装入物レベルを減尺した後休風し、炉壁損傷部に下記表１２に示す成分の不定形耐火物を３０トン吹付け補修した。この際、不定形耐火物のリバウンドロスは、目視で判断したところ約１５％（４．５トン）であった。なお、通常操業時のスラグ成分は、上記表１に示した通りである。
【００３０】
【表１２】
作業終了後、操業を再開したところ、第１回目の出銑作業時に出銑口からのスラグの排出速度は、通常休風立上げ時の１．１トン／分から０．５トン／分と遅くなり、炉内通気性が悪化して送風圧力は、通常休風立上げ時の２．０ｋｇ／ｃｍ2 から２．４ｋｇ／ｃｍ2 と上昇し、原燃料の降下異常が見られた。後に調査したところ、第１回目に排出したスラグ成分は、表１３に示すように、Ａｌ2 Ｏ3 は１８％であった。
【００３２】
【表１３】
【発明の効果】
以上説明したように、本発明の高炉炉内壁補修時における高炉操業方法では、高炉の休風時に高炉炉内壁を耐火物で吹付け補修するに際し、耐火物が炉内壁に接着せずに高炉内に落下する量と、高炉内への落下時のスラグ成分を予測し、それが高炉内で溶融する時に、通常のスラグ成分とほぼ同じになるように、吹付けを実施する直前及び直後、または、直前或いは直後に、フラックス原料を単独、或いは、コークス又は鉱石と共に高炉内に装入するので、炉内通気性が悪化して送風圧力が上昇することや、装入物の降下異常を生じることがなく、円滑な操業を達成することができる。また、本発明方法を適用することによって、炉内壁損傷補修が容易となり、より高炉の炉命延長が図れる。[0001]
BACKGROUND OF THE INVENTION
In the present invention, when the inner wall of a blast furnace is repaired by spraying with a refractory, air permeability, liquid permeability, and deterioration of unloading caused by falling refractory into the blast furnace (hereinafter referred to as “rebound loss”) are reduced. The present invention relates to a blast furnace operation method at the time of repairing an inner wall of a blast furnace that can be controlled and performed smoothly.
[0002]
[Prior art]
In recent years, damage to the inner wall of the furnace has become severe due to the prolonged life of the blast furnace. Therefore, Japanese Patent Publication No. 60-24161 discloses a method for spraying an indeterminate refractory to a damaged part of the furnace inner wall, but 5 to 50% of the refractory sprayed to the inner wall of the furnace is in the damaged part of the furnace wall. There was a problem that it fell onto the furnace interior without adhering and stuck on the surface of the raw material in the furnace, impeding the air permeability and liquid permeability in the blast furnace after the restart of operation.
[0003]
In view of this, the present applicant disclosed in JP-A-10-46217 a method of crushing the rebound loss fixed on the surface of the raw material in the furnace to improve the air permeability in the blast furnace.
[0004]
[Problems to be solved by the invention]
However, the component of the rebound loss is the refractory component itself, and generally has a high melting point, so that it is difficult to melt in the blast furnace even if crushed. In addition, since the melted material also has poor fluidity, it deteriorates the air permeability and liquid permeability in the blast furnace, and sometimes causes abnormal lowering of the charged material such as stagnation of the descent and rapid descent. Therefore, it is not preferable to deposit the rebound loss in the blast furnace as it is in order to perform smooth blast furnace operation.
[0005]
The present invention has been made in view of the above-described problems, and the component of the rebound loss is a component of the flux raw material charged into the blast furnace, and is adjusted so that the slag component is substantially the same as that during normal operation. An object of the present invention is to provide a method for operating a blast furnace at the time of repairing an inner wall of a blast furnace that can improve slag properties, improve air permeability and liquid permeability in the blast furnace, and perform smooth operation.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned purpose, the blast furnace operation method at the time of repairing the inner wall of the blast furnace according to the present invention predicts the amount of rebound loss and the slag component when falling into the blast furnace, and this fallen rebound loss is detected in the blast furnace. Just before and immediately after the refractory spraying, or just before or after the refractory spraying, the flux raw material alone or together with coke or ore is loaded into the blast furnace so that it becomes almost the same as the normal slag component when melting. Enter. And by doing in this way, the slag property in a blast furnace is improved, and the air permeability and liquid permeability in a blast furnace become favorable.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The amount of rebound loss is usually about 10 to 30% of the spraying amount in the results of the present inventors.
The component of the rebound loss is a refractory component itself, and in general, a spray material used for repairing the inner wall of a blast furnace is aluminum oxide (Al 2 O 3 : melting point 2050) which is a high melting point compound. ° C) is contained in an amount of about 20 to 70%, and the melting point is 1600 ° C or higher. Therefore, rebound loss is difficult to melt in the blast furnace.
[0008]
On the other hand, the content of Al 2 O 3 in ordinary blast furnace slag is about 10 to 16%, and is mixed with other components such as CaO, SiO 2 and the like to form a slag having a melting point of 1400 ° C. or less. Melting in the blast furnace is easy. In addition, when the Al 2 O 3 content in the blast furnace slag is high, the fluidity of the blast furnace slag is deteriorated, resulting in poor separation from hot metal, poor lead and the like.
[0009]
Therefore, in order to reduce the slag component including rebound loss to the same component as usual, particularly Al 2 O 3 content of 16% or less, the flux of limestone, quartzite, serpentinite, etc. containing a lot of CaO or SiO 2 The raw material or blast furnace slag must be singly or mixed and charged into the blast furnace immediately before and immediately after spraying the refractory, or immediately before or after, to adjust the slag component. The charging material is not limited to the flux material and blast furnace slag, but may be mixed with coke or ore.
[0010]
The blast furnace operating method at the time of repairing the blast furnace inner wall of the present invention is based on the above-described concept, and when the blast furnace inner wall is repaired by spraying with a refractory when the blast furnace is closed, the amount of rebound loss, Predict the slag component at the time of falling into the blast furnace, and when this rebound loss melts in the blast furnace, just before and immediately after the spraying, so that it becomes almost the same component as the normal slag component, or Immediately before or after, the flux material is charged alone or together with coke or ore into the blast furnace.
[0011]
In the blast furnace operation method at the time of repairing the inner wall of the blast furnace according to the present invention, the predicted amount of rebound loss is predicted with reference to past performance values, experimental values, estimated values of refractory manufacturers, and the like.
[0012]
The blast furnace operation method at the time of repairing the inner wall of the blast furnace of the present invention is performed immediately before and immediately after the spraying, or immediately before the rebound loss is melted in the blast furnace so as to be the same as the components of the normal blast furnace slag. Alternatively, immediately after the flux raw material is introduced into the blast furnace alone or together with coke or ore, the slag properties in the blast furnace are improved, and the air permeability and liquid permeability in the blast furnace are improved.
[0013]
【Example】
Hereinafter, the blast furnace operating method at the time of repairing the inner wall of the blast furnace according to the present invention will be described based on examples.
Example 1
In a blast furnace with an internal volume of 2700m 3 and a furnace diameter of 8.4m, after the charge level was reduced below the damaged part of the furnace wall, the wind was stopped, and dry blowing repair of the irregular refractory was planned for the damaged part of the furnace wall. . At this time, by adopting the method of the present invention, assuming a rebound loss of 15% (4.5 tons) for a spraying amount of 30 tons, the first slag component is shown in Table 1 below during normal operation. Of the flux materials, serpentine and limestone were charged into the blast furnace just before spraying. The charged serpentine and limestone components are shown in Table 2 below, the charged amounts are shown in Table 3, and predicted slag components after the serpentine and limestone are charged are shown in Table 4 below. As a method for determining the amount of serpentine and limestone charged, first, determine the total amount of limestone and serpentine so that Al 2 O 3 usually has the slag content, and then CaO / SiO 2 The ratio of limestone and serpentine is determined so that it is the normal slag value.
[0014]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
When the operation was resumed after the work was completed, the air permeability in the furnace deteriorated and the blast pressure increased, and there was no decrease in raw fuel drop abnormalities (stagnation or rapid drop), and the first discharge The slag component was almost the same as the slag component during normal operation, and the operating parameters returned to normal operation. Table 5 shows the slag components discharged for the first time.
[0019]
[Table 5]
(Example 2)
In a blast furnace with an internal volume of 2700m 3 and a furnace diameter of 8.4m, after the charge level was reduced below the damaged part of the furnace wall, the wind was stopped, and dry blowing repair of the irregular refractory was planned for the damaged part of the furnace wall. . At this time, by adopting the method of the present invention, the rebound loss is assumed to be 15% (4.5 tons) with respect to the spraying amount of 30 tons, and the first slag component is shown in Table 1 above during normal operation. In order to make it almost the same as the slag component of the above, the serpentinite and limestone of the components shown in Table 2 above in the flux raw material, and the amount of heat decrease such as heat removal from the furnace body due to the long rest time As a guarantee, coke was charged into the blast furnace just before spraying. Table 6 shows the amounts of the serpentine and limestone charged, and Table 7 shows the predicted slag components after charging the coke, serpentine and limestone.
[0021]
[Table 6]
[Table 7]
When the damaged part of the furnace wall was observed after the wind break, the damage was more severe than expected, and the spraying amount was decided to be 40 tons (assumed rebound loss amount was 6.0 tons). Therefore, if only the amount of serpentinite and limestone shown in Table 6 is charged, the expected slag component shown in Table 7 is not obtained, but the slag component shown in Table 8 below is expected. Is done. In this forecast, Al 2 O 3 in the slag is 16.6%, which is significantly higher than in normal operation, and the air permeability in the furnace deteriorates, leading to an increase in blast pressure and abnormal drop in raw fuel. Therefore, serpentinite and limestone were inserted immediately after spraying. Table 9 shows the charging amount immediately after spraying, and Table 10 shows the expected slag components after charging the serpentine and limestone.
[0024]
[Table 8]
[Table 9]
[Table 10]
When the operation was resumed after the completion of the work, the air permeability in the furnace deteriorated and the blast pressure did not increase, and there was no decrease in abnormal drop in raw fuel, etc. The slag component discharged for the first time was normal operation It was almost the same as the slag component of the time, and the operating specifications returned to normal operation. Table 11 shows the slag components discharged for the first time.
[0028]
[Table 11]
(Conventional example)
In a blast furnace with an internal volume of 2700 m 3 and a furnace port diameter of 8.4 m, after the charge level was reduced below the damaged part of the furnace wall, it was rested, and an amorphous refractory with the components shown in Table 12 below was placed in the damaged part of the furnace wall. Repaired 30 tons. At this time, the rebound loss of the irregular refractory was about 15% (4.5 tons) as judged visually. The slag component during normal operation is as shown in Table 1 above.
[0030]
[Table 12]
When the operation was resumed after the completion of the work, the slag discharge rate from the tap outlet during the first taping work was slowed down from 1.1 tons / min at the time of normal wind up to 0.5 tons / min. As a result, the air permeability in the furnace deteriorated, and the blowing pressure increased from 2.0 kg / cm 2 at the normal start-up time to 2.4 kg / cm 2 . When investigated later, as shown in Table 13, the slag component discharged at the first time was 18% Al 2 O 3 .
[0032]
[Table 13]
【The invention's effect】
As described above, in the blast furnace operation method of the present invention when repairing the blast furnace inner wall, when the blast furnace inner wall is repaired by spraying the blast furnace with a refractory when the blast furnace is closed, the refractory does not adhere to the furnace inner wall. The amount of slag falling into the blast furnace and the slag component at the time of dropping into the blast furnace are predicted, and when it is melted in the blast furnace, it is almost the same as the normal slag component, immediately before and after the spraying, or , Immediately before or immediately after, the flux material is charged alone or together with coke or ore into the blast furnace, so that the air permeability in the furnace is deteriorated and the blowing pressure is increased, or abnormal lowering of the charged material is caused. Smooth operation can be achieved. In addition, by applying the method of the present invention, it is easy to repair the damage on the inner wall of the furnace, and the life of the blast furnace can be extended.
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| JP07495299A JP3750405B2 (en) | 1999-03-19 | 1999-03-19 | Blast furnace operation method during blast furnace inner wall repair |
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| JP07495299A JP3750405B2 (en) | 1999-03-19 | 1999-03-19 | Blast furnace operation method during blast furnace inner wall repair |
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| JP3750405B2 true JP3750405B2 (en) | 2006-03-01 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| KR100395111B1 (en) * | 2000-12-23 | 2003-08-21 | 주식회사 포스코 | Method for improving permeability in blast furnace after repair of the furnace wall |
| KR100797360B1 (en) * | 2001-09-07 | 2008-01-22 | 주식회사 포스코 | Blast Furnace Operation Method For Early Securing Steady Operation Temperature |
| CN102134620B (en) * | 2010-10-19 | 2012-05-23 | 新兴铸管股份有限公司 | Blast furnace shaft upper part rapid heating for producing lining by wet method |
| CN103468839B (en) * | 2013-09-06 | 2015-03-11 | 武汉钢铁(集团)公司 | Method for removing caked slag with thickness not smaller than 500mm from blast furnace body |
| CN106755676B (en) * | 2016-11-25 | 2019-01-29 | 武汉钢铁有限公司 | A kind of sweep-out method of blast-furnace shaft knot thickness |
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